Problems with power - Model B - Backfeed from USB hubs?

[edmun]

Hi Guys


I don't know. I am getting more and more confused when I am trying to summarize information from this forum. All topics says something different and I am just lost.


I already have some details that some of the USB hubs provide back power through the actual usb lead going from USB hub to Raspberry Pi. And I've heard that this current is not using any fuses.
Because I am constantly working, when I am coming back home, I feel myself like I won't touch any electronic devices until the next day (sorry.. working in IT is not always the best for geeks). Therefore when I am thinking about checking the raspberry really carefully once coming back home, it feels like it is at least 4-5 hours project with checking almost everything that could be physically checked.



Ok.. enough of crying here let's introduce you to my setup.
I am using Raspberry Pi Model B.
Have couple of 8GB SD Card (Using only Genuine Sandisks 8-10 class).
Raspbian has been installed directly from distribution (not by Noobs).


Looking at the leaflet attached to Raspberry,
I should use a power supply unit with 0.7A - 1.1A.
Of course there is a different info at the Raspberry's FAQ (it has been updated so the leaflet from the box might be out of date):

Code: Select all

I. POWER


1. What are the power requirements?
The device is powered by 5v micro USB. Exactly how much current (mA) the Raspberry Pi requires is dependent on what you hook up to it. We have found that purchasing a 1.2A (1200mA) power supply from a reputable retailer will provide you with ample power to run your Raspberry Pi for most applications, though you may want to get a 2.5A (2500mA) if you want to use all 4 USB ports on the Model B without using an external powered USB hub.


Typically, the model B uses between 700-1000mA depending on what peripherals are connected, the Model B+ has slightly more efficient power circuits as well as more available USB ports and can use between 600-2000mA, and the model A can use as little as 500mA with no peripherals attached. The maximum power the Raspberry Pi Model A and B can use is 1 Amp, so if you need to connect a USB device that will take the power requirements of the Raspberry Pi above 1 Amp then you must connect it to an externally powered USB hub. Alternatively, the maximum power the Model B+ can use is 2 Amps before needing to connect devices to an externally powered USB hub.


The power requirements of the Raspberry Pi increase as you make use of the various interfaces on the Raspberry Pi. The GPIO pins can draw 50mA safely (that is 50mA distributed across all the pins! An individual GPIO pin can only safely draw 16mA), the HDMI port uses 50mA, the camera module requires 250mA, and keyboards and mice can take as little as 100mA or over 1000mA! Check the power rating of the devices you plan to connect to the Pi and purchase a power supply accordingly. If you’re not sure, buy a powered hub.

and also information about the "backfeed"

Code: Select all

2. Can I power the Raspberry Pi from a USB Hub?


It depends on the hub. Some hubs comply with the USB 2.0 Standard and only provide 500mA per port, which may not be enough to power your Raspberry Pi. Other hubs view the USB standards more like guidelines, and will provide as much power as you want out each port. Please also be aware that some hubs have been known to “backfeed” the Raspberry Pi. This means that the hubs will power the Raspberry Pi through its USB cable input cable, without the need for a separate micro-USB power cable, and bypass the voltage protection. If you are using a hub that “backfeeds” to the Raspberry Pi and the hub experiences a power surge, your Raspberry Pi could potentially be damaged. The additional information column provides details as to whether the Raspberry Pi can be powered directly off the hub and if the hub “backfeeds” power to the Raspberry Pi.

Previously I was using two USB powered hubs from Belkin
and Amazon Kindle USB charger (with Micro USB cable) with 0.8A current.
The USB hubs model is F5U404-BLK. 4 USB ports on each hub.
At the back of them, there is a B port for USB cable going to the host.

Image taken from amazon.com

USB hubs are powered by PSU from DVE, which provides 5V with 2.5A per each hub.


Those two USB hubs were connected to two USB ports in Raspberry.
USB hubs have a backfeed, so once connected to Raspberry Pi it starts at the same time as the hubs.
To one of the powered HUB I have connected three 2.5" SATA2 HDDs in USB 2.0 Enclosures.
One of the enclosures is using Y-type USB cable (2 usb plugs).
So to one of the hubs I had 2x 2.5" HDDs with a single USB connection and 1x 2.5" with double USB.
To my second USB hub - I have only connected a 3.5" HDD which was powered by it's own power supply and this one does not provide any backfeed power.



Currently I have started again from a scratch and formatted all the SD cards, installed Raspbian and connected my Raspberry only to my new USB charger which is 5V, 2.1A.



Previously I had 3 power supplies connected to my Raspberry.
So:


Power in:
Two powered usb hubs (2x 2.5A) + Amazon Kindle USB charger 0.8A - total 5.8A


Power out:
Raspberry model B takes max 1A.
3x 2.5" HDD (with one of them connected by two USB male plugs, so 4x) - 4x500mA = 2A
1x 3.5" HDD with it's own power supply.


Even with the power for the USB powered led and the hub itself, this should add addditional 2x100mA = 200mA


So in total we have 5.8A in and 3.2A taken.


During any work with this setup - I had constant problems with SD card being damaged/corrupted and almost every weekend I had to image the SD card again and again,

to have Raspberry Pi working. Really irrytating once you are away from home for 2 weeks and you know that once you will come back - your weekend will be lost to recover Raspberry again.

Not even mentioning all the downtime .



Apart from SD cards being corrupted (and I will straight away mention that there isn't any problem with the SD cards itself) the USB drives were dismounting themselves randomly from time to time,

and only a reset was bringing them back online.



I went through many USB hubs, different connection configurations, finally I have said - ENOUGH.
--------------------------

So I've started from a scratch. Currently Raspberry PI is using the same SD cards, but apart from network cable and the power supply cable (Micro USB), nothing else is connected to it.

I have spent again money and I bought a different power adapter which has 5V 1A (with a nice looking name "kit:")
Image below shows black model with 2.1A

image taken from mobilefun.co.uk

This Raspberry PI is already working fine for 2 weeks without any problems at all.


Now I am preparing myself to connect the USB hubs and after that - the USB harddrives again.
Recently I have received new 2.5" HDDs and I have also bought some new USB enclosures (this time even with USB 3.0 which does not make any difference with Raspberry)
I am afraid to use the same powered usb hubs, because they provide this backfeed power.
I can't locate any more reasons of my previous issues.

Because powered USB hubs are not some cheap ones and I think Belkin is one of those companies which do provide a good quality products,
I also do not believe that issue lies within the usb hubs.

So going to the end of this long story - is there any reason that I should cut off the power backfeed from those powered usb hubs?
If yes - which exact voltage has to be removed? USB plug has +5, Data +, Data - and Ground

Image taken from frontx.com

If I am correct - that means that +5V should be removed. Anyone could confirm?

I would be happy to discuss this matter until I will take the Raspberry Pi's case off and start to measure T1 and T2

[fruitoftheloom]

Yes cut the red wire: http://www.raspberrypi.org/forums/viewt ... 54#p420735

Just a point of intterest - Class 4 SD Cards are deemed more suitable for the Pi

[pluggy]

This will get the purists going, but if it works, leave it be. 5 volts is 5 volts, yes it breaks the rules, but stuff the rules.

[edmun]

but if it works, leave it be. 5 volts is 5 volts, .

that's the question:

When I had everything connected - it wasn't working.
And I still can't rectify if the backfeed is the reason.

That's why now I am using a different "charger" but leaving all the rest as it is, but this time,
I am trying to connect one peripheral after another to find the reason.
Also - I do not want to rip off the cable and remove 5V without a confirmation that this is a reason.
Was hoping to get some feedback from the users
otherwise I will have not so good looking cable to quite expensive USB hub (sorry. I have overpaid for them)

I do no want to go live to see that Raspberry Pi will keep playing up again.

[Lob0426]

As to powering;
You need to decide if you are going to back feed or not. Back-powering works just fine, with the Model B rev 2.0 (two mounting holes), with no modifications. The newer Model B+ does not. Your original explanation says you knew you had back-power and you were using the Model B's power (third PSU) port also. This is not a good idea as the voltage between these two PSU's is probably different. If both hubs are back-powering now you have possibly three different voltages. This could be where you are having the card corruption issues from.

My suggestions:
Power plan 1.
No back-power; cut the red wire in the USB cables to both hubs. PSU's power both hubs, no PSU to the RasPi. Power the RasPi from one of the hubs ports with an A to micro B cable. Make sure to keep this cable short so that you do not lose as much voltage to the RasPi. make sure that you only have one power source into the RasPi. Turning the hub off turns the RasPi off. The other hub will need to be turned off separately. Put them on a power strip so you can turn everything off at the same time.

Power plan 2:
Back-power; cut the red wire in one of the hubs USB cable. PSU's to both hubs. Make sure the hub that is back-powering has a short cable. Again I would recommend using a power strip.

These wall warts are pretty inneficient so you want to use as few as you can to power your project. On average the PSU's eat as many watts as the RasPi they are powering, sometimes more!

You want only one power source into the Raspberry Pi.

Run only a mild overclock. High over clocks seem to cause some of the corruption issues. I usually use 900MHz to 950MHz settings, of course this depends on your RasPi.

You need to have the latest updates! These have many fixes including for the card corruption issues identified much earlier.

You should be making regular backups. I use Win32DiskImager. Depending on the card size and speed it can take 10 minutes to 30 minutes to complete a backup. Restoring can take up to 45 minutes, but it is a walk away until it is done process. It should not be taking you hours to rebuild your SD Card. I backup, then update, test the card, then backup again. An hour of time, but most of it is in the background while I do other things.

Use class 4 or class 6 cards for the best overall stable performance. I use the class 6 cards, usually SanDisk. Do not buy the card over the Internet cheap. Buy it from a reputable local store. There are fake Branded cards out there that are not ever going to work reliably. Save the cheap cards for playing around with other projects, not your 24/7 machine.

My WordPress Server has been running reliably for a very long time, the latest iteration has been up for at least 6 months. Failures are due only to power outages. I do not have card corruptions at all! So you should be able to get the same performance from yours!

I hope these suggestions help you out.

Richard

[edmun]

As to powering;
You need to decide if you are going to back feed or not. Back-powering works just fine, with the Model B rev 2.0 (two mounting holes), with no modifications. The newer Model B+ does not. Your original explanation says you knew you had back-power and you were using the Model B's power (third PSU) port also. This is not a good idea as the voltage between these two PSU's is probably different. If both hubs are back-powering now you have possibly three different voltages. This could be where you are having the card corruption issues from.

What I am trying to explain is -
Previously I had connected USB charger directly to Raspberry Pi by it's Micro USB port,
where both powered USB hubs were back powering the Raspberry PI also by the two USB ports on the Raspberry itself.
Please do not confuse that I am adding any additional cables from the hubs to Raspberry Pi,
like a cable from HUBs USB port->Micro USB port at the Raspberry. I have never done it this way.

HDDs are connected to the hubs,
and from a hub there is one A-B cable
which is going from the hubs port to a normal USB port at Raspberry Pi.
Like a normal HUB use:
If hub has 4 ports, I connect 4 usb devices to the hub and than one cable is going to Raspberry's USB port.

Also - I always use extension leads, with filters and power switches

My suggestions:
Power plan 1.
No back-power; cut the red wire in the USB cables to both hubs. PSU's power both hubs, no PSU to the RasPi. Power the RasPi from one of the hubs ports with an A to micro B cable. Make sure to keep this cable short so that you do not lose as much voltage to the RasPi. make sure that you only have one power source into the RasPi. Turning the hub off turns the RasPi off. The other hub will need to be turned off separately. Put them on a power strip so you can turn everything off at the same time.

Your suggestion is to completely resign from separate PSU?

I was thinking in the opposite way.
My way of thinking was, that the powered usb hubs (even if they have more current available), then those are really not stable figures, due to hard drives not being used constantly in the same way (HDDs are not consuming the same amount of power)
Unless I am missing something.
I always thought that if I will connect 3 drives (each 500 mA) to a powered USB hub which provides 2.5A and also there will be cable going in the same way as to those hard drives, but to the Raspberry Pi, then the current hitting Raspberry PI will be random between 1A to around 2.5A, depending on how much the drives will be consuming at the moment.
If all 3 HDDs will be spinning with 100% power and taking 1.5A, then 2.5A - 1,5A leaves 1A for Raspberry PI, but once one of the hard drives will slow down and stop randomly seeking on the sectors, it will consume less than 500mA, so to Raspberry PI, the current which will be passed - will suddenly be not 1A, but say 1.1A or 1.2 and so on.
And from what I have heard - micro USB port on Raspberry is fused one,
where 2 USB ports for peripherals are not secured?

Power plan 2:
Back-power; cut the red wire in one of the hubs USB cable. PSU's to both hubs. Make sure the hub that is back-powering has a short cable. Again I would recommend using a power strip.

These wall warts are pretty inneficient so you want to use as few as you can to power your project. On average the PSU's eat as many watts as the RasPi they are powering, sometimes more!

You want only one power source into the Raspberry Pi.

I am now even more confused.
Why would I depend on the power from only one of the hubs?
Again I have a question - what is the advantage of powering Raspberry by the hub if I have a good stable USB charger which currently is not causing any problems.
This is really an open question.

Run only a mild overclock. High over clocks seem to cause some of the corruption issues. I usually use 900MHz to 950MHz settings, of course this depends on your RasPi.

Never overlocked. Always runs on standard

You need to have the latest updates! These have many fixes including for the card corruption issues identified much earlier.

Raspbian installed and updated by wheezy raspbian - not by the Noobs.

You should be making regular backups. I use Win32DiskImager. Depending on the card size and speed it can take 10 minutes to 30 minutes to complete a backup. Restoring can take up to 45 minutes, but it is a walk away until it is done process. It should not be taking you hours to rebuild your SD Card. I backup, then update, test the card, then backup again. An hour of time, but most of it is in the background while I do other things.

I am using dd script which creates img file for me - which afterwards I am deploying onto SD card with the use of SD Card Reader.
(please see http://www.raspberrypi.org/forums/viewt ... 17#p483717 for the details)

With the use of Win32DiskImager it takes around 10 minutes,
but unplugging everything, opening cases, boxes, wardrobes and detaching "corrupted" SD card takes more time for me than actual imaging the SD card. And again - even if the imaging process is not time taking - please keep in mind that I am away from home. I can only depend on restoring backups 3 times per week when I am arriving home late (around 1am)

Use class 4 or class 6 cards for the best overall stable performance. I use the class 6 cards, usually SanDisk. Do not buy the card over the Internet cheap. Buy it from a reputable local store. There are fake Branded cards out there that are not ever going to work reliably. Save the cheap cards for playing around with other projects, not your 24/7 machine.

I have mentioned that I am using only genuine cards.
No cheap china replacements which looks the same but are twice cheaper on ebay.
(yes - I am aware of the "cheap" Sandisk look alike cards overflowing the market.

I hope these suggestions help you out.

Thanks a lot.
I hope that you won't take a feeling that I am criticising anything.
for today I really "do have enough" (of work) - and believe - I am trying my best to sound and type friendly ;(
(when I click preview and read my writing before I click "Submit", it looks for me like I have this negative attitude to everything)

I just really do like get to the bottom of something, before going further with a live system.
Especially that the first one is a total unreliable failure FOR me and OF me in the same time.

Sadly said just because of a limited time for actual private life (which is depressing (ehh.. we are living in a strange times...) ) - I can't sit with my Raspberry and have a "date" with it with measuring voltage, current checking, T1 and T2 points and hoping that I will notice where the issue lies just by be lucky

I hope that everyone will have a nice weekend !
All best to everyone

[Lob0426]

You appear to be unsure if you are back-powering. It is very simple to find out. Plug one hub into the RasPi USB with no other power supplies. Plug the hub PSU in. See if the RasPi lights up. If you see the LED lights then you are receiving back-power.

A 3 PSU power system is what you appear to want. 1 to the RasPi and 1 each to the hubs. The first step would be to eliminate the chance of back-powering altogether. Cut the red wires in the USB cables between your hubs and your RasPi.

Your original power solution (if there is a back-power from the hubs) is presenting three different PSU's to the RasPi. The chances that all three are at exactly the same voltage is pretty low. This means power surges or drops from the hubs are seen by the RasPi. None of this is good for your RasPi or its SD Card. This is very likely the cause of your corruption issues.

You only want one power source into your Raspberry Pi. Period. This is what I believe is causing your troubles.

So my suggestions, in the previous post, was to choose a power option then stick to it. Either back-power the system, or power it conventionally. You probably need to use conventional power for your system. One method to do that is to get the power from one of your hubs rather than a totally separate PSU.

As to the power usage of your HDD's they may run at 500ma after spinup (maybe slightly less), but they probably draw 1000ma+ (1A at 5V) during spinup. So they are exceeding a single 2.5A PSU, at least for a short period. So at boot your drives are pulling more current than a single hub's PSU is designed for. This could be browning out your RasPi and causing crashes. These crashes are causing the corruptions. The figures above are pretty much standard for USB powered HDD.

I perfectly understand what Back-Powering is. I used it to power my Raspberry Pi server for about nine months and it performed reliably. I have modified two RasPi's that only back-power. There are several forum posts about back-powering. I have several pages of of information about back-powering on my server. You should take a look at this information, if you intend to use back-powering as your power system. If you do not intend to Back-power then just stop the hubs power from reaching your Raspberry Pi.

[W. H. Heydt]

A 3 PSU power system is what you appear to want. 1 to the RasPi and 1 each to the hubs. The first step would be to eliminate the chance of back-powering altogether. Cut the red wires in the USB cables between your hubs and your RasPi.

Alternatively, get a better grade of USB hub. Ones that don't try to back power in the first place. I've been using this one (http://www.mcmelectronics.com/product/83-12399) together with the Adafruit 5.25v power supply for the Pi. Haven't had any problems.

Your original power solution (if there is a back-power from the hubs) is presenting three different PSU's to the RasPi. The chances that all three are at exactly the same voltage is pretty low. This means power surges or drops from the hubs are seen by the RasPi. None of this is good for your RasPi or its SD Card. This is very likely the cause of your corruption issues.

Virtually guaranteed that they won't match and you'll have power flowing every which way, with current going places you probably don't want it to.

[Lob0426]

My server is using the Adafruit PSU. I does work very well.

I think he believes that the multiple power sources will give him a fail safe power system. Unfortunately it just does not work that way. Instead they are causing his card corruption issues.

[edmun]

I think he believes that the multiple power sources will give him a fail safe power system. Unfortunately it just does not work that way. Instead they are causing his card corruption issues.

Hmm. sorry but not.. Please do not treat me as a dumb.
I was always believing that having one power source which is tested and it's working fine is much netter then having a power source which powers something else.
That's why I constantly insist to use 1A Micro USB charger and remove completely backfeed from powered USB hubs

anyway even with all the help and all your time wasted on me, I believe that the only way to resolve all my issues will be to leave Raspberry connected to the power (Micro USB charger) but remove voltage going from powered USB hubs to Raspberry as an additional power. And one more time - I am not using any of the USB ports from the hub to charge my Raspberry Pi.
The only problem is that if I will connect USB charger to micro usb port of RP, connect powered USB hub to any of the USB ports at RP, I can unplug the Micro USB charger and raspberry pi is still working. For me - it's called backfeed.

And in my humble opinion - it is a reason of all energy / power problems I do have...

[mikronauts]

I think your problems can be boiled down to: only power your Model B from ONE power adapter

If you are back powering from one of your powered hubs, do not use a micro-USB power adapter for the Pi, and cut the +5 from the other powered hub to the Pi.

Supplying power to the Pi from more than one power source is a recipe for problems.

I've also back powered Model A's & Model B's from nice powered hubs that had power to spare, but I made sure I was not feeding the Pi power from more than one source.

[fruitoftheloom]

I think he believes that the multiple power sources will give him a fail safe power system. Unfortunately it just does not work that way. Instead they are causing his card corruption issues.

Hmm. sorry but not.. Please do not treat me as a dumb.
I was always believing that having one power source which is tested and it's working fine is much netter then having a power source which powers something else.
That's why I constantly insist to use 1A Micro USB charger and remove completely backfeed from powered USB hubs

anyway even with all the help and all your time wasted on me, I believe that the only way to resolve all my issues will be to leave Raspberry connected to the power (Micro USB charger) but remove voltage going from powered USB hubs to Raspberry as an additional power. And one more time - I am not using any of the USB ports from the hub to charge my Raspberry Pi.
The only problem is that if I will connect USB charger to micro usb port of RP, connect powered USB hub to any of the USB ports at RP, I can unplug the Micro USB charger and raspberry pi is still working. For me - it's called backfeed.

And in my humble opinion - it is a reason of all energy / power problems I do have...

Just cut the power line in the hub to stop back-feeding.......

[edmun]

Hmm.. if I won't have any problems I should schedule this in for Saturday but can't promise ... Thanks guys ! Please drop in to Birmingham in UK for some homemade beer !

[Lob0426]

Not trying to treat you as "dumb", but no solution seems to be acceptable to you to date.

EDIT:
Reading back on your prior posts you actually have answered your own problem. You are running the RasPi without the hubs on a dedicated PSU and it has run for two weeks. No hubs and it works. You also have determined that there IS a back-feed.

You need to reevaluate the number of HDD's that can be run from each hub. Three HDD's on one and Two on another hub. The one with three HDD's is overloaded at startup. The HDD's are drawing 3A at startup and your PSU is rated at 2.5A, if the rating is really correct!
CUT THE RED WIRE, then try your hubs in the system!


A quote from you!

Why would I depend on the power from only one of the hubs?

You should not be depending on the hubs for any power at all.

Another quote from you

And I still can't rectify if the backfeed is the reason.

It most likely is the problem. You basically have all three PSU's connected together (The RasPi is that connection). If one hub has too much power being drawn on its PSU (never mind the PSU ratings, many have been tested, and are wrong or are over rated) it draws from the power pool that you have created. The RasPi is the nexus of that power. So a "brownout" on the hub is "seen" by the RasPi. That means the RasPi browns out then crashes! Enough crashes and your SD card becomes corrupted.

A possible solution is to try to isolate the hubs power (back-power) from the RasPi. Then see if the corruption issues stop, or improve! It may not be the whole issue. Until you try one of the suggestions in this forum post you will most likely learn nothing that will lead to a cure for your problems!

Another possible solution is to change to a lower class of SD card.

Most of my, and others, suggestions are part of diagnosing your problems, not reasons to argue. You can either try them or not.

You will have to try something new or your problems will continue!

Usual Diagnostic steps for the Raspberry Pi:
1. Most people do not realize that having more than 1 power source into their RasPi causes problems. Can cause corruption!
2. Most people swear that they have legitimate branded cards. Mostly they do, some got taken!
3. Many people have reported corruption issues with Class 10 SD cards.
4. Most people believe their power source is working just fine, so it is the RasPi that isn't.
5. Most people believe they have the most updated OS, usually they do not.
EDIT:
6. Extreme overclocking has been identified as a possible source of card corruption

I have been suggesting items you should give a second look at.

You have the option to power it normally or to back-power. Because of all the USB connections you have, and their power draw, you should use a separate PSU directly to the RasPi. This means you need to stop the back feed or buy hubs that do not back-power. Then you test from there. If you are using DD to backup then I do not understand why it is taking you hours to repair your system, It should be much shorter than that. I understand that you have it all buried in a closet or something.

I would do it differently as I am very practiced and experienced with back-powering Raspberry Pi's. BUT I would have followed these suggestions IF I encountered corruption issues. AND HAVE, used these very steps in diagnosing RasPi problems.

Richard

[edmun]

Lob0426 thank you for such a comprehensive reply.
You don't even know how much I appreciate the comments and involvment of the people willing to help.
I am really glad that the topic was not just left apart, even when I could be irritating and not listening.
Therefore (to all participants) I would like to say a really big thank you for all supporters.
Unfortunately I won't be able to perform the changes during this weekend :/
My boss has just made his requirements and literally explained to me that even if I do deserve to receive a raise, he can't do it for the next 12 months. So tomorrow I am working from 10 to 18 + travel which leads to be available for "the company" for over 12 hours, with the knowledge that my boss is playing up with me and I won't be able to look into my Rasp during this weekend.

But again.... one more time - big thank you for everything. And I promise that once I will make the changes - I will let everyone know !


P.S. Please do not think that I am denying any solutions provided. I have (sadly) become a person that does not listen to a solution, untill it has some "basic" roots and reasons which are pointing to a solution. I have spend to much time in my life applying solutions without the background. That's why I might be a little sceptic. Believe me - there's nothing personal

p.s.2 For the help provided I really offer some beer for anyone that helped me. Please send me a private message if capable to claim the reward from around B23 5SN

May the force be with everyone:

[Lob0426]

Even with my simple WordPress web server it took many hours to have it perform up to a decent standard. I tried many different builds before I was happy with it. It has had several iterations of hardware also. I built a version for a Panda Board ES. The Panda Board was very fast with WordPress. Then I made tutorials to make it easier for others.

So most of us understand how time consuming it can be to set up a Raspberry Pi server!

The Raspberry Pi allows a very power efficient 24/7 solution. It also allows a very cost efficient solution for those that cannot afford to spend hundreds on a server setup.

Stick with it when you get the time, you will be able to make it work!

[edmun]

I promised I will be back (I just hate topics where there is a problem and at the end, there isn't any feedback from the autor of it).

Because weekend is coming, I was thinking that I will go a little further.
First time (in the last few weeks) I have found 1 hour of time for myself, so I've started with making changes in the USB cable.
Few days ago I have prepared my HDDs and finally decided that for the beginning,
I will operate on one 2.5" HDD SATA in USB enclosure to see how it will go.

Afterwards if everything will be working fine - I will add one more which should fit my requirements for now.

So - my Raspberry will be connected to the power supply (USB charger with Micro USB cable) and one Belking powered USB hub, with 5V wire being cut off in the cable going from the hub to the rasbperry pi.

I wasn't happy to cut my "Genuine Belkin USB cable":


but finally I managed to open it from the USB plug side:





Now I don't know how to gain access to the wires.
I am thinking that I've just lost around £25 for two USB hubs, which won't fit my requirements
with Raspberry Pi and I have to look after another one that won't provide backfeed.
Or - use a not powered hub (lets call it "pink") that does not provide a backfeed - and connect my Belkin powered ones to this pink hub one and than this pink hub to the Raspberry PI? Does it make any sense at all?

[BMS Doug]

but finally I managed to open it from the USB plug side:





Now I don't know how to gain access to the wires.
I am thinking that I've just lost around £25 for two USB hubs, which won't fit my requirements
with Raspberry Pi and I have to look after another one that won't provide backfeed.
Or - use a not powered hub (lets call it "pink") that does not provide a backfeed - and connect my Belkin powered ones to this pink hub one and than this pink hub to the Raspberry PI? Does it make any sense at all?

You could buy some male USB plugs and cut the cable then solder a new plug onto the cable (minus the red 5V wire) and seal with a hot glue gun. fairly cheap, except for buying a soldering iron and a hot glue gun.

Alternatively you could (very carefully) strip a section of outer sheaf to expose the inner wires, then cut the red wire. if it all goes wrong you can default to plan A.

Afterwards you can cover the stripped section with heat shrink (and as I'm writing this I realise how much I like having the right tools to do this sort of thing).

[Lob0426]

Some people have had success with using tape to cover just the 5V pin in the USB connector to the hub. This might work for you !

[edmun]

You could buy some male USB plugs and cut the cable then solder a new plug onto the cable (minus the red 5V wire) and seal with a hot glue gun. fairly cheap, except for buying a soldering iron and a hot glue gun.

Afterwards you can cover the stripped section with heat shrink (and as I'm writing this I realise how much I like having the right tools to do this sort of thing).

yeah. That also bothers me. Buying additional equipment to solve just one small thing. My wife probably will try to kill me, once she will hear that I need to buy "another toy". Of course I have soldering iron, but because I've never had to use a heat gun, never bought one.


I will check with this cheap china USB hub that is not a powered one and see how it goes.

[DougieLawson]

How about cutting the contact between the socket and the PCB or the wire and the PCB in your hub?

[BMS Doug]

yeah. That also bothers me. Buying additional equipment to solve just one small thing. My wife probably will try to kill me, once she will hear that I need to buy "another toy". Of course I have soldering iron, but because I've never had to use a heat gun, never bought one.

I will check with this cheap china USB hub that is not a powered one and see how it goes.

I guess I'm lucky that my wife doesn't mind me buying things, I suppose that it helps that I use the tools to fix the kids toys and other stuff. (Recently made a wedding present for a friend).

[eysi]

How would I know if the USB powered hub is compatible by looking at its specs with the raspberry pi without backfeeding? I just want to have a usb hub that can't give power supply to the raspberry pi because I want to connect a mini usb cable as its power supply.

[fruitoftheloom]

How would I know if the USB powered hub is compatible by looking at its specs with the raspberry pi without backfeeding? I just want to have a usb hub that can't give power supply to the raspberry pi because I want to connect a mini usb cable as its power supply.

http://elinux.org/RPi_Powered_USB_Hubs

[Lob0426]

The down and dirty way is to plug the RasPi into the wall, then plug the powered hub into your RasPi USB (powered up too). Unplug the RasPi from the wall. If the lights stay on or the whole RasPi stays on then you are getting a back feed.